The present invention is a power roof ventilator which is installed on the roof of a restaurant to exhaust the grease- and smoke-laden air from the hoods of ranges and grills below. Such ventilators are installed where a vertical discharge of the air is required. Typical installations are found on the roof of all types of commercial and institutional kitchens, such as restaurant and cafeteria, fast food, hotel and motel, bakery, delicatessen, school, hospital and military.
In many instances the above named kitchens are located in the vicinity of residential neighborhoods or recreational areas or in a garden-type setting, where the dining takes place, and is enjoyed in an outdoor setting. While the heretofore known ventilators do an adequate job in exhausting the air from the hoods of the kitchens, they also create a nuisance by exhausting the foul smelling smoke into the vicinity of the restaurant and its surroundings which is very objectionable because the smoke can spread around and within quite an area. For example, in a typical motel setting, there is a grill operating on the premises and the guests enjoying the swimming pool are subjected to the foul smelling smoke being exhausted on the roof which detracts from the enjoyment of the pool and leads to complaints. One such ventilator is known and produced by ILG INDUSTRIES DIVISION and identified as the type UBC centrifugal upblast power roof ventilator. The UBC power ventilator is said to have a powerful vertical discharge exhaust of contaminated air high above roof levels preventing recirculation into adjacent air intakes. However, the smoke that is exhausted is exhausted as is and is not treated at all. Grease-laden smoke consists of micro particles which may cling to each other and form a certain density with the surrounding air and under certain weather conditions, such as high humidity, may form a blanket of foul smelling air over a considerably large area.